JOURNAL OF THE CHILEAN CHEMICAL SOCIETY, vol.59, no.4, pp.2705-2709, 2014 (SCI-Expanded)
Three simple, quick and sensitive methods are described for the spectrophotometric determination of vildagliptin (VLD) in pharmaceutical preparations. The methods are based on formation of colored charge transfer (CT) complexes between VLD as n-electron donor and chloranilic acid ( CA), tetrachloro-1,4-benzoquinone (p-chloranil), 7,7,8,8-tetracyanoquinodimethane ( TCNQ) as pi-acceptors. The colored products were quantitated spectrophotometrically at 520, 535 and 842 nm for CA, p-chloranil and TCNQ methods, respectively. Optimization of different experimental conditions were investigated. Beer's law was obeyed in the concentration range of 20-250 mu g mL(-1), 25-400 mu g mL(-1) and 20-500 mu g mL(-1) for CA, p-chloranil and TCNQ methods, respectively. The formation of the CT-complexes and the sites of interactions were confirmed by elemental analysis using IR, H-1 NMR spectroscopy. Validity of the methods in terms of specificity, linearity, accuracy, precision, robustness, limit of detection and limit of quantitation were evaluated. Good recoveries were obtained for all of the methods indicating that no interference was observed from concomitants usually present in dosage forms. The methods were applied successfully to the determination of VLD in pharmaceutical preparations.